In order to address environmental problems such as global warming, which has been attracting attention in recent years, large facilities including office buildings and commercial facilities are required to operate with less power consumption.
About 21% of energy consumed by such large facilities is used by lighting equipment. Accordingly, a reduction of the energy consumed by lighting equipment is important as an anti-global warming measure.
Lighting equipment is now undergoing a transition from lighting fixtures using fluorescent bulbs to lighting fixtures using light emitting diodes (LEDs).
In contrast to the fluorescent bulbs, the life of the lighting fixtures using LEDs is not shortened by rapidly switching the lighting fixtures on and off. Furthermore, the amount of light of the lighting fixtures using LEDs can be easily adjusted. Due to these characteristics, it can be expected that LED fixtures will reduce the energy consumption of the lighting equipment by careful control of turning off the lighting equipment or reducing the amount of light.
For example, there are many illumination control systems which use infrared motion sensors to determine the presence of people in the room for controlling the switching on and off of fixtures. In the illumination control systems, the lighting equipment is turned on in the presence of people in the room and is turned off in the absence of people.
The infrared motion sensors are capable of precisely sensing moving people such as walking people but in many cases do not sense motionless people such as people who are doing office work.
Moreover, the action of detected people in the room cannot be analyzed with an infrared motion sensor. Accordingly, it is not possible to control the amount of light according to the movement of the detected people. This will sometimes reduce the convenience to people staying in the room or will prevent the provision of the high energy-saving effect.